William h



Patented Oct. 23, 1923.

UNITED STATES PATENT OFFICE.

WILLIAM II. MAY, or ATLANTA, GEORGIA, AssIGNoE To LENA o. MAY, or ATLANTA,

` GEORGIA.

PISTON.

Application i'lled September 'To all whom t may concern.

Be it known that I, WILLIAM H. MAY, a citizen of the United States, residing at At lanta, in the county of Fulton and State of Georgia, have invented certain new and useful Improvements in Pistons, of which the following is a specification.

This invention relates to improvements in pistons.

The primary object of this invention is the provision of a'piston of relatively simple construction, which embodies an improved cylinder lubricating arrangement.

A further object of this invention is the provision of a very durable piston which is so constructed that explosion pressures thereon are concentrated axially of the piston so that an explosive charge may be most effectively utilized. y

A further object of this invention is the provision of an improved type of piston including upper and lower portions of exactly the same external diameter whose surfaces are adapted for sliding contact within an engine cylinder, the improved piston em-` bodying anoil pocket circumferentially intermediate the upper and lower portions thereof which has a cushioning effect upon the piston during reciprocatory movement thereof, and thereby eliminate piston slap and irregular deteriorating movements thereof.

A further object of this invention is the provision of an improved piston of the above mentioned character which embodies an improved arrangement for feed of lubricant into an oil pocket provided circumferentially thereabout. Y

Other objects and advantages of this invention will be apparent during the course of the following detailed description.

In the accompanying drawing, forming a part of this specification, and wherein similar reference characters designate corresponding parts throughout the several views.

Figure 1 is a side elevation of the improved piston, showing the same as operatively used in the cylinder chamber of an internal combustion engine.

Figure 2 is a vertical cross sectional view taken through the improved piston.

Figure 3 is a transversecross sectional view taken on the line 3-3 of Figure 2.

Figure 4 is an enlarged fragmentary Sec- 9, 1922. serial No. 587,070.

tional view of an upper portion of the improved piston showing the cooperative construction of the details thereof.

` In the drawing, wherein for the purpose of illustration is shown but the preferred embodiment of this invention, the letter A,A designates the improved piston pivotally mounted upon a connecting rod B, and adapted for slidable reciprocatory movement within thechamber 10 of a cylinder 11 of an internal combustion engine casing C.

Referring to the 'piston A, the same includes the cylindrical shaped casing 15, which may be formed of approved material, such as cast iron or aluminum. The casino' 15 includes the cylindrical shaped top and bottom portions 16 and 17, whose exterior surfaces are exactly ofthe same diameter, so that the same are in sliding contact with the walls of the cylinder chamber 10 during movement of the piston A within the cylinder 11. The top wall 18 of the upper piston portion 16 is provided with a concaved surface 19, which may be struck from a radius of aproximately twenty inches. The Concaved surface 19 intersects the outer circumferential surface of the upper portion 16 to provide a cylindrical acute edge 2O about the top of the piston casing 15. The relatively deep circumferential groove 23 is provided annularly in the circumferential portion 16 of the casing 15 adapted to receive the piston ring 24 of any approved constructiton.

The intermediate portion 25 of the casing 15 is provided with an outer surface 26 of less diameter than the outer surfaces of the upper and lower cylindrical portions 16 and 17 respectively. This portion 25 is disposed immediately below the piston ring groove 23, although an annular ring portion 28 is provided immediately below the groove 23, the outercircumferential surface of which is of slightly greater diameter .than the diameter of the surface 26, although of less diameter than the external diameter of the upper piston portion 16. Aligning wrist pin bearings 30 and 31 project interiorly of the intermediate portion 25, ybeing a part thereof and which are adapted for receiving a horizontally disposed wrist ypin 33v for attaching the connecting rod B to the piston casing 15 within the chamber 34 of said casing. A circumferential series of oil ducts or ports 35 are provided in the intermediate portion 25, said ports 35 being of tapered formation and the larger diameter of said ports opening outwardly upon the surface 26 with the reduced ends of said ports opening into the chamber 34 of the casing 15 immediately below a horizontal annular shelf 38 which is provided by an annular projection 39 of the upper cylinder portion 16; said portion 39 having' the p iston ring groove 23 therein, as can readily be seen in Figure 2 of the drawings. lt is to be noted that the lower marginal. edge 40 provided bv the ring shaped portion 28 d1- a-Inetrically intersects all of the oil ducts or ports 35.

The lower annular marginal edge of the cylinder portion 17 is provided with an inwardly bevelled surface 42, intersecting the exterior surface of the lower piston portion 17 to provide a circumferential sharp edge 43, said surface 42 converging upwardly inwardly. of the chamber 34v of the piston, casing 15.

In operation, the piston casing 15 is connected to the connecting rod B by means of a wrist pin 33, as can readily be understood, and is adapted for sliding in the chamber of the cylinder 11. As the piston casing reciprocates withinl the chamber 10, the lubricant upon the walls of the chamber 10 on the downstrolrev of the piston A will be scraped by the annular acute edge43 so that said oil 'will be thrown upwardly over the bevelled surface 42 and directed i into the chamber 34 provided in the piston casingr 15. Due to the inclination of the surface 42, the lubricant will be forcibly thrown into the chamber 34 to engage the substantially horizontal shoulder 38, so that the lubricant is directed to the sina-llerends of the oil ducts 35, and may exit into the chamber 50 which is provided intermediate the outer surface 26 of the pist-on portion and the inner walls of the cylinder chainber 10, as can readily be seen from Figure 1 of the drawing. The oil entering this chamber 50 is effectively retainedl therein duev to the fact that thev outer circumferential surfaces of the piston upper and lower portions. 16 and 17 are in snug engagement with the cylinder walls, so that the oil therein provides an effective cushion, the function of which is to lubricate the walls of the cylinder 11, and to buf. any tendencyv of the piston to vibrate, thereby eliminating. slap which is found in. most types of pistons andV materially lessens the eliciency of gine operationand. results in shorteningr the life ofthe same. Referring to Figure 4 the drawing, it can. readilyI be seen that the outer surface of the portion 28 of the piston casing 15 is of less. diameter than the outer surface of. the upper piston portion 16, so that as the piston descends within the cylinder-10, an. annular lower marginal edge surface 53 of the piston ring 24 extends outwardly from the surface of the piston portion 28 to scrape excessive lubricant from the side walls of the cylinder chamber 1G, said lubricant being forced into the pocket 50. Should there be an excessive supply of lubricant 'within the chamber of pocket 50, the same will exit through the apertures into the piston interior, 34 as can readily be understood. By the provision of the annular ring portion 28 upon the bodyof the piston A, the oil or lubricant is effectively regulated, so that the same cannot approach the piston ring 24 in excessive quantities, while at the same time, the flow of the lubricant into the pocket or chamber is su'tlicient so that the same may be retained in quantities to perform the function for which the piston is provided. In addition, the annular ring portion 28 insures that excess oil within the pocket 50 may be directed through the ducts 35 into the piston interior 34.

From the foregoing description of this invention, .it can be seen that the piston is provided with a top surface which will effectively regulate the pressure incident to an explosive charge so that strains will not unnecessarily occur upon the piston ring, but will be directed axially of the piston casing itself. The oil ducts 35 not only act as inlet but as outlet passageways, and are preferably drilled with a O taper. The oil pocket 50 is effectively filled with lubricant, at all times during engine operation.

Various changes in the shape, size and arrangement of parts may be made to the form of invention herein shown and described, without departing from the spirit of the invention or the scope of the claims.

I claim:

1. As an article of manufacture, a piston of the hollow casing type including an inner chamber, said piston having a circumferential series of tapered ducts communicating with theiinterior of said piston, and an annular shoulder extending within said piston casing immediately over said ducts, the piston casing havingr the lower edge thereof bevelled to upwardly converge axially of the piston and providing a sharp marginal edge about the lower end ofthe casing.

2. A piston comprising a body portion of the hollow type including` cylindrical shaped upper and lower portions of exactly the same exterior diameter, said upper portion having thetop surface thereof concaved and provided with an annular groovev extending inwardly ofthe outer circumference therel of, said piston body including an intermediate portion` having an exterior surface of reduced diameter with respect to the outer vided in said intermediate portion immediately below the groove in said upper piston portion, said upper piston portion having a shoulder extending inwardly thereof ton so that said oil may be directed through 5 immediately above said ducts, the lower pissaid ducts over the outer surface of the inton portion having the lower marginal termediate portion.

edges thereof acutely formed and provided with an upwardly converging surface WILLIAM H. MAY.

adapted to receive oil or lubricant scraped from the cylinder Wall for directing the same against the shoulder Within said pis- 

